- I don't have a different display adapter to test with.
- If I reboot while the Surface is connected to the HDMI display, I get the same results, no mouse pointer.
- This is complicated. After rebooting with the Surface connected to HDMI, I set the mouse pointer to the default setting and then I observed that the mouse pointer was invisible as before. I then rebooted leaving the HDMI connected and that time the mouse pointer was visible for a bit and then disappeared. I rebooted again and the pointer stayed. I then set the pointer back to Magnified and it remained visible, and I rebooted and it remained visible.
I have one other observation, and that is when the HDMI display is attached, the gesture signon tracks aren't displayed (finger, not mouse). Also, when I say that the Mouse pointer is invisible, I only mean the Default mouse pointer. The text insert pointer and the wait pointer sometimes displayed when the default pointer wouldn't.
Also I should note that the mouse pointer is visible on the lock screen under any circumstance, only disappearing for good after the Desktop is displayed, or a bit after the Start screen.
At this point, I have a mouse pointer with HDMI, but I am not sure how I could tell someone else how to fix the same problem, or whether mine will stay fixed.